Dynamic advertisement routing

ABSTRACT

Dynamic advertisement routing is disclosed. For example, a plurality of internet protocol (“IP”) addresses associated with respective plurality of target nodes is stored in a routing pool. Each IP address in the routing pool is pinged through each of first and second load balancer network interfaces. Network routes associated with target nodes are updated based on a first plurality of ping responses. Communications sessions are established with target nodes through respective network routes. IP addresses are pinged and respective latencies in a latency cache are updated based on a second plurality of ping responses. A first request directed to the plurality of target nodes is received and is determined to be sent to a first target node based on the latency cache forwarded to the first target node via the first network route.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/815,063, filed on Nov. 16, 2017 which is a continuation of U.S.patent application Ser. No. 15/463,820, filed on Mar. 20, 2017, theentire contents of each of which is hereby incorporated by reference intheir entirety for all purposes.

BACKGROUND

The present disclosure generally relates to advertising on networkaccessible devices. As microprocessors have become more efficient, andnetwork connectivity more prevalent, an ever increasing amount ofdevices now have internet or intranet enabled capabilities and features.With the network capabilities of network accessible devices, comeopportunities for users to consume content, and therefore opportunitiesfor publishers of content to advertise to these users. Advertisers arepresented with ever increasing opportunities to reach their increasinglyaccessible consumers through a myriad of network accessible devices usedby these consumers on a daily basis. As such, computing and networkingspeed is of paramount importance for advertisers to take advantage ofopportunities to present advertisements as these opportunities arise.

SUMMARY

The present disclosure provides a new and innovative system, methods andapparatus for dynamic advertisement routing. In an example, a pluralityof internet protocol addresses including first, second, and thirdinternet protocol addresses are stored in a routing pool. In theexample, the first internet protocol address is associated with a firsttarget node of the plurality of target nodes, the second internetprotocol address is associated with a second target node of theplurality of target nodes, and the third internet protocol address isassociated with a third target node of the plurality of target nodes.Each of the plurality of internet protocol addresses in the routingpool, including at least the first, second, and third internet protocoladdresses, is pinged through each of a first load balancer networkinterface and a second load balancer network interface. At least one ofa first network route to the first target node, a second network routeto the second target node, and a third network route to the third targetnode is updated based on a first plurality of ping responses. First,second, and third communication sessions are established with therespective first, second and third target nodes, respectively throughfirst, second, and third network routes. The first, second, and thirdinternet protocol addresses are pinged. First, second, and thirdlatencies in a latency cache are updated based on a second plurality ofping responses. A request directed to the plurality of target nodes isreceived. The request is determined to be sent to the first target nodebased on the latency cache. The request is then forwarded to the firsttarget node via the first network route.

Additional features and advantages of the disclosed method and apparatusare described in, and will be apparent from, the following DetailedDescription and the Figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a block diagram of a dynamic advertisement routing systemaccording to an example of the present disclosure.

FIG. 2A is a block diagram of dynamic network route detection accordingto an example of the present disclosure.

FIG. 2B is a block diagram of dynamic network target selection accordingto an example of the present disclosure.

FIG. 3 is a flowchart illustrating dynamic advertisement routingaccording to an example of the present disclosure.

FIG. 4 is a flow diagram illustrating target discovery and routeselection in a dynamic advertisement routing system according to anexample of the present disclosure.

FIG. 5 is a flow diagram illustrating target prioritization throughlatency detection in a dynamic advertisement routing system according toan example of the present disclosure.

FIG. 6 is a flow diagram illustrating dynamic request handling in adynamic advertisement routing system according to an example of thepresent disclosure.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

As network accessible devices increasingly gain popularity,opportunities to advertise on such network accessible devices increase.With the vast variety of devices capable of presenting audio and visualadvertisements (“ads”), comes numerous opportunities to display ads, andalso competition for the advertising opportunities or ad slots. Responsetime may therefore be critical for maximizing both the likelihood ofsecuring an ad slot as well as the effectiveness of a given ad slot. Asusers typically expect perceivably immediate responses when accessingcontent online, the entire process for negotiating, selecting, anddisplaying an ad may typically be completed in under one second. In atypical day, billions of ads may be served to consumers on networkaccessible devices. To handle these requests for ads, publishers, adagencies, and/or advertisers may typically implement load balancers todistribute network traffic to individual nodes to handle individualrequests.

In a typical advertising exchange implementation, a user on a networkaccessible device may access content supplied by a publisher. Thepublisher may incorporate ads in the content, and seek prospectivebuyers for the ads in the content in real-time while the content isloading. An ad agency may, upon receipt of a request to bid on a givenad slot, seek advertisers either directly or through an advertisingexchange to purchase the ad slot. In an example, to maintain a positiveuser experience for the content, a publisher may require response withina certain critical time threshold. In an example, network latency mayaccount for a significant proportion of the time spent handling a givenrequest.

A typical server may be limited in the number of network connections itmay maintain with a given target based on, for example, an availabilityof ports with which to establish these connections. In a typicalexample, a given network connection may require a handshaking processthat may be required to navigate several internal system queues beforean initial handshake message is even sent, and several messagesgenerally need to be exchanged to establish a secure networkcommunication session. For example, a request may generally originatefrom software requiring a network connection, the software's request maybe queued by the operating system to be packaged for a network interfacesuch as a network interface card (“NIC”), the NIC may then put therequest into an outgoing queue before being sent. The NIC and the targetserver may then perform a multi-step handshake to authenticateencryption keys, each leg of which incurs the full transmission latencybetween the NIC and the target server (e.g., at least 3 messagestransmitted for a secure socket layer (“SSL”) connection). Uponsuccessful handshake, each message is then queued by each layer of thesystem once again before the software sees the response (e.g., NICreceiving queue, system queue, and software queue). In all, a brand newconnection could easily take 100 ms-200 ms to establish, even whereservers are located relatively close to each other.

A typical network connection may be established by and between twoservers, each of which is identifiable through a unique InternetProtocol (“IP”) address, which may be a sequence of delimited numericalor hexadecimal digits. For example, IPv4 addresses are typically in theform of four 8-bit digits (e.g., 0-255) delimited by periods (e.g.,255.255.255.0). Meanwhile, IPv6 addresses are typically in the form ofeight groups of four hexadecimal digits, each group consisting of 16bits and separated by colons (e.g.,fiff:ffff:ffff:ffff:fiff:ffff:ffff:0). In various other examples, anyform of uniquely identifiable address may be used to direct messagesbetween two servers, for example a Media Access Control (“MAC”) address.In a typical example, a company such as an advertiser may have itsnetwork facing systems represented by a Uniform Resource Locator (“URL”)where the IP address of individual servers is hidden behind a domainname and host name representative of the company (e.g.,www.enginegroup.com). A Domain Name System (“DNS”) may typically bequeried by a network interface to resolve a host name URL into an IPaddress. One advantage is that servers may be interchangeablysubstituted for each other by updating the DNS without interrupting theavailability of the host name URL (e.g., www.enginegroup.com). However,for purposes of routing requests where milliseconds are significant, aquery to DNS to resolve a host name URL may take upwards of 10 ms,typically a similar amount of time to sending a message directly to aknown IP address. In addition, a company such as an advertiser or adagency may host dozens, even hundreds or thousands of servers behind agiven host name URL, with each individual system potentially offeringsignificantly different performance characteristics. For example, aparticular server may be undergoing routine maintenance or running abackup slowing down responses. Multiple servers behind the same hostname URL may also be located in different cities or data centers andtherefore response latency may be significantly different due tophysical proximity.

Network traffic between any two given physical locations may alsotypically be routed through a series of different relays between point Aand point B. Along each step of physically relaying a message from pointA to point B, decisions are made regarding which relay node should nextreceive the message. Often times several possible paths are weightedequally at decision time, and therefore a given path from point A topoint B may be different each time a connection is established. Forexample, a relay node X in Washington D.C. between point A (e.g., inVirginia) and point B (e.g., in New York City) may forward a message toeither one of relay node Y (e.g., in Secaucus, N.J.) and node Z (e.g.,in Princeton, N.J.) before arriving at a final destination in New YorkCity. On a typical day, the Secaucus relay node Y may perform betterthan the Princeton relay node Z, for example, because the Secaucus relaynode Y may have higher bandwidth capacity into New York City. However, acompany may initiate a massive data backup operation through theSecaucus-New York City connection slowing down traffic for anyone elseusing the same connection, thereby making the path through node Ztemporarily faster. In a typical scenario, relay node X may be unawareof any factors preferencing relay node Y over relay node Z or vice versaand select a sub-optimal route.

As a result, a typical network connection may incur several hundredmilliseconds of overhead as a result of handshaking and sub-optimalrouting that may ultimately frustrate efforts to display ads in a givenad slot. The present disclosure aims to address these inefficiencies intypical network routing systems to significantly cut down on networklatency between a load balancer and a target node, thereby increasingthe proportion of ad slots responded to in a timely manner. For example,an example system performing dynamic advertisement routing may employmultiple network interfaces (e.g., physical and/or virtualized NICs) toincrease port availability and therefore active connections resulting inreduced handshaking for new connections. By implementing multiple NICs,a system is additionally able to establish multiple connections to thesame target, which results in additional network routes beingestablished between the source system and the target as the variousconnections are routed along different relays. Having multiple pathsavailable to select from allows for the selection of a fastest route fora request at a particular given moment. In addition, with theavailability of various different connections between source and target,current performance characteristics of each connection may be assessedto determine performance grades for groups of connections, which maythen allow for the prioritization of requests based on the performancegrades of connections allowing for the optimization of timely responses.In an example, by implementing dynamic advertisement routing asdisclosed in the present disclosure, a typical advertisement requestresponse loop may see latency reductions of 50% or more, for examplefrom 500 ms-1000 ms down to 150 ms-250 ms. In addition, a largereduction may be seen in requests that respond too late to be used tofill an ad slot or time out altogether due to periodic verifications ofeach connection.

FIG. 1 is a block diagram of a dynamic advertisement routing systemaccording to an example of the present disclosure. In an example,dynamic advertisement routing in system 100 may be performed by loadbalancer service 140, routing service 141, and latency service 142 inconjunction with latency cache 150 and routing pool 155. In an example,load balancer service 140, routing service 141, and latency service 142may execute on a virtual machine (“VM”) 116 that is hosted by ahypervisor 190 which executes on one or more of a plurality of hardwarenodes (e.g., nodes 110, 112, and 114). In the example, load balancerservice 140, routing service 141, and latency service 142 may connect totarget nodes over network 105. In an example, load balancer service 145,routing service 146, and latency service 147 may represent a second setof services executing on VM 118 that are functionally similar to loadbalancer service 140, routing service 141, and latency service 142.

In an example, network 105 may be any type of network, for example, apublic network (e.g., the Internet), a private network (e.g., a localarea network (LAN) or wide area network (WAN)), or a combinationthereof. In an example devices connected through network 105 may beinterconnected using a variety of techniques, ranging from apoint-to-point processor interconnect, to a system area network, such asan Ethernet-based network. In an example, load balancer service 140,routing service 141, and latency service 142 may execute on anyvirtualized or physical hardware connected to network 105. In anexample, load balancer service 140, routing service 141, and latencyservice 142 executes on VM 116 which executes on nodes 110, 112 and 114.The system 100 may include one or more interconnected hosts (e.g., nodes110, 112 and 114). Each nodes 110, 112 and 114 may in turn include oneor more physical processors (e.g., CPU 120A-E) communicatively coupledto memory devices (e.g., MD 125A-C) and network interfaces (e.g., NIC130A-C). As used herein, physical processor or processors (CentralProcessing Units “CPUs”) 120A-E refer to devices capable of executinginstructions encoding arithmetic, logical, and/or I/O operations. In oneillustrative example, a processor may follow Von Neumann architecturalmodel and may include an arithmetic logic unit (ALU), a control unit,and a plurality of registers. In an example, a processor may be a singlecore processor which is typically capable of executing one instructionat a time (or process a single pipeline of instructions), or amulti-core processor which may simultaneously execute multipleinstructions. In another example, a processor may be implemented as asingle integrated circuit, two or more integrated circuits, or may be acomponent of a multi-chip module (e.g., in which individualmicroprocessor dies are included in a single integrated circuit packageand hence share a single socket). A processor may also be referred to asa central processing unit (CPU).

As discussed herein, a memory device 125A-C refers to a volatile ornon-volatile memory device, such as RAM, ROM, EEPROM, or any otherdevice capable of storing data. Each node may also include input/output(“I/O”) devices capable of providing an interface between one or moreprocessor pins and an external device, the operation of which is basedon the processor inputting and/or outputting binary data. CPUs 120A-Emay be interconnected using a variety of techniques, ranging from apoint-to-point processor interconnect, to a system area network, such asan Ethernet-based network. In an example, NICs 130A-C may be physicalnetwork interfaces capable of connecting each of nodes 110, 112, and 114to another device, either a physical node (e.g., nodes 110, 112, or 114)or a virtual machine (e.g., VMs 116 and 118). In an example NICs 130A-Cmay allow nodes 110, 112, and 114 to interconnect with each other aswell as allowing nodes 110, 112, and 114 as well as software executingon the nodes (e.g., load balancer service 140, routing service 141, andlatency service 142) to connect to remote systems such as target nodesover network 105. Local connections within each of nodes 110, 112 and114, including the connections between a processor 120A and a memorydevice 125A-B and between a processor 120A and a NIC 130A may beprovided by one or more local buses of suitable architecture, forexample, peripheral component interconnect (PCI). In an example, NICs130A-C may be virtualized as virtual network interfaces 187A-D. Forexample, physical NIC 130A may act as a relay for a message to or fromvirtual network interface 187A, with virtual network interface 187Ahaving a different IP address from NIC 130A. In an example, eachphysical NIC may support multiple virtual network interfaces. In anexample, VM 116 may have eight, sixteen, sixty-four or more virtualnetwork interfaces. In the example, additional virtual networkinterfaces result in additional possible routes between VM 116 and atarget node. In a typical example, if only one network route is used,the one network route may deliver a median level of performance. In anexample where ten network routes are examined, probability dictates thatselecting the best performing network route of the ten options maytypically result in a performance in the ninetieth percentile ofpossible network routes, which may well be a significant performanceboost as compared to the fiftieth percentile.

In computer systems (e.g., system 100), it may be advantageous to scaleapplication deployments by using isolated guests such as virtualmachines and/or containers that may be used for creating hostingenvironments for running application programs. Typically, isolatedguests such as containers and virtual machines may be launched toprovide extra compute capacity of a type that the isolated guest isdesigned to provide. Isolated guests allow a programmer to quickly scalethe deployment of applications to the volume of traffic requesting theapplications as well as isolate other parts of system 100 from potentialharmful code executing within any one virtual machine. In an example, aVM may be a robust simulation of an actual physical computer systemutilizing a hypervisor or a component (e.g., a virtual machine manager)that executes tasks commonly executed by hypervisors to allocatephysical resources to the virtual machine. In an example, VMs 116 and118 may be virtual machines executing on top of physical hosts (e.g.,nodes 110, 112 and 114), possibly with a hypervisor 190 executingbetween the virtualized layer and the physical hosts. In an example,load balancer service 140, routing service 141, and/or latency service142 may be further virtualized (e.g., in a container).

In an example, load balancer services 140 and 145, routing services 141and 146, and latency services 142 and 147 may be connected with alatency cache 150 and a routing pool 155 stored in a memory 132. In anexample, memory 132 may be a physical memory store on memory devices 125A-C. In another example, memory 132 may be a virtual memory store invirtual memories 185A-B. In the example, latency cache 150 may furtherinclude latencies 160, 162, 164, and 166, and routing pool 155 mayfurther include IP addresses 170, 172, 174, and 176. In an example,latency cache 150 and routing pool 155 may be stored in volatile storagesuch as Random Access Memory (“RAM”) allowing fast access. In anexample, a copy of latency cache 150 may further be stored in cachememory directly on CPUs 120A-C for faster access for routing requests.

In an example, non-transitory copies of latency cache 150 and routingpool 155 may be stored in any suitable type of database, for example, arelational database. In some examples, latency cache 150 and routingpool 155 may be stored in non-volatile storage (e.g., hard disk or flashmemory) in addition to volatile storage (e.g., RAM or cache memory). Forexample, a copy of routing pool 155 may be stored in non-transitorystorage that is synchronized and shared between routing service 141 androuting service 146 on separate VMs 116 and 118, but routing service 141and routing service 146 may each load a working copy of routing pool 155into local RAM. The latency cache 150 and the routing pool 155 may bestored in a database associated with a database management system(DBMS). A DBMS is a software application that facilitates interactionbetween the database and other components of the system 300. Forexample, a DMBS may have an associated data definition languagedescribing commands that may be executed to interact with the database.Examples of suitable DMBS's include MariaDB®, PostgreSQL®, SQLite®,Microsoft SQL Server® available from MICROSOFT® CORPORATION, variousDBMS's available from ORACLE® CORPORATION, various DBMS's available fromSAP® AG, IBM® DB2®, available from the INTERNATIONAL BUSINESS MACHINESCORPORATION, etc. In an example, the latency cache 150 and routing pool155 may be stored in a database organized as a formal database with aschema such as a relational schema with defined tables, indices, links,triggers, various commands etc. In some examples, latency cache 150 androuting pool 155 may not be organized as a formal database, but mayinstead be an alternative storage structure capable of holding theinformation stored in latency cache 150 and routing pool 155, includingbut not limited to a file, folder, directory, registry, etc. In anexample, latency cache 150 and routing pool 155 is stored innon-volatile storage.

System 100 may run one or more VMs 116 and 118, by executing a softwarelayer (e.g., hypervisor 190) above the hardware and below the VMs 116and 118, as schematically shown in FIG. 1. In an example, the hypervisor190 may be a component of a host operating system executed by the system100. In another example, the hypervisor 190 may be provided by anapplication running on the host operating system, or may run directly onthe nodes 110, 112 and 114 without an operating system beneath it. Thehypervisor 190 may virtualize the physical layer, including processors,memory, and I/O devices, and present this virtualization to VMs 116 and118 as devices, including virtual processors (“VCPU”) 180A-F, virtualmemory devices 185A-B, virtual network interfaces 187A-D.

In an example, a VM 116 may be a virtual machine and may execute a guestoperating system which may utilize the underlying virtual centralprocessing unit (“VCPUs”) 180A-C, virtual memory device (“V. Memory”)185A, and virtual network interfaces 187A-B. Load balancer service 140,routing service 141, and latency service 142 may run as applications onVM 116 or may be further virtualized and execute in containers.Processor virtualization may be implemented by the hypervisor 190scheduling time slots on one or more physical processors 120A-E suchthat from the guest operating system's perspective those time slots arescheduled on a virtual processors 180A-C.

A VM 116 may run on any type of dependent, independent, compatible,and/or incompatible applications on the underlying hardware and hostoperating system. In an example, load balancer service 140, routingservice 141, and/or latency service 142 running on VM 116 may bedependent on the underlying hardware and/or host operating system. Inanother example, load balancer service 140, routing service 141, and/orlatency service 142 running on VM 116 may be independent of theunderlying hardware and/or host operating system. In an example, loadbalancer service 140, routing service 141, and/or latency service 142running on VM 116 may be compatible with the underlying hardware and/orhost operating system. Additionally, load balancer service 140, routingservice 141, and/or latency service 142 running on VM 116 may beincompatible with the underlying hardware and/or OS. The hypervisor 190may manage memory for the host operating system as well as memoryallocated to the VM 116 and guest operating systems. In an example, VM118 may be another virtual machine similar in configuration to VM 116,with VCPUs 190D-F, virtual memory 185B, and virtual network interfaces187C-D operating in similar roles to their respective counterparts in VM116. The VM 116 may host load balancer service 145, routing service 146,and latency service 147.

FIG. 2A is a block diagram of dynamic network route detection accordingto an example of the present disclosure. System 200 as illustrated inFIG. 2A shows routing service 141 determining preferred network routesto various IP addresses of advertiser 220. In an example, discoveryservice 241 and routing service 141 may be implemented in any suitableprogramming language (e.g., Java, C, C++, C-sharp, Visual Basic,structured query language (SQL), Pascal, common business orientedlanguage (COBOL), business process execution language (BPEL), businessprocess model notation (BPMN), complex event processing (CEP), jBPM,Drools, etc.). In an example, discovery service 241 may periodicallyestablish connections with a host name URL for advertiser 220, allowingDNS to direct discovery service 241 to a random IP address and node ofadvertiser 220. In an example, each time discovery service 241successfully connects to an IP address, the IP address may be added torouting pool 155 (e.g., IP addresses 170, 172, 174, and 176). In theexample, discovery service 241 may establish connections without actualpayload data (e.g., through pinging the host name URL), or discoveryservice 241 may send live payload data (e.g., low priority requests withlow latency sensitivity). In an example, sending actual data may furthervalidate that a given IP is operational as compared to a ping. In someexamples, a frequency at which discovery service 241 is executed may bereduced after new results become sufficiently infrequent to indicatethat a vast majority of possible IP addresses have been discovered andadded to routing pool 155.

In an example, routing service 141 may have access to two differentvirtual network interfaces (e.g., V. network interfaces 187A and 187B)through which routing service 141 may connect to advertiser 220. In theillustrated example, advertiser 220 operates three separate hardwarenodes 210, 211, and 212, on which three copies of an ad service (e.g.,ad services 230, 232 and 235) are executing. In the example, each node210, 211, and 212 has one or two NICs (e.g., NICs 250, 252, and 255A-B)through which ad services 230, 232, and 235 receive requests. In anexample, each NIC (e.g., NICs 250, 252, and 255A-B) may be associatedwith a separate IP address (e.g., IP Addresses 170, 172, 174, and 176).In the example, routing service 141 may be unable to distinguish whethertwo IP addresses (e.g., IP addresses 170 and 172) representing two NICs(e.g., NICs 250 and 252) belong to the same copy of an ad service (e.g.,ad service 230) executing on one node 210, or to two different copies ofthe ad service (e.g., ad services 230 and 232) executing on differentnodes (e.g., node 210 and 211). In an example, each physical NIC (e.g.,NICs 250, 252, and 255A-B) may be virtualized as multiple virtual NICseach with a respective IP address and set of ports. In an example, eachnode may also include more NICs than depicted (e.g., one node mayinclude eight or more NICs). In an example, routing service 141 may pingeach IP address 170, 172, 174, and 176 in routing pool 155 through eachof virtual network interfaces 187A and 187B to determine whetherconnecting to each respective NIC 250, 252, and 255A-B is faster throughvirtual network interface 187A or 187B. In the example, routing service141 may set the faster route as a preferred route (e.g., network routes260, 262, 264, and 266) in a routing table 270. In an example routingtable 270 may be a component of a guest operating system of VM 116 onwhich routing service 141 executes.

FIG. 2B is a block diagram of dynamic network target selection accordingto an example of the present disclosure. System 201 as illustrated inFIG. 2B shows latency service 142 determining latencies (e.g., latencies160, 162, 164, and 166) and by extension performance levels of variousIP addresses of advertiser 220. In an example, dynamic routes between VM116 and advertiser 220 have already been discovered by routing service141 as illustrated in FIG. 2A. In the example, network route 260 mayindicate a connection from virtual network interface 187A to NIC 250,network route 262 may indicate a connection from virtual networkinterface 187A to NIC 255A, network route 264 may indicate a connectionfrom virtual network interface 187B to NIC 252, and network route 266may indicate a connection from virtual network interface 187B to NIC255B. In an example, latency service 142 may then ping each IP address(e.g., IP addresses 170, 172, 174, and 176) in routing pool 155 using asystem default network route (e.g., network routes 260, 262, 264, and266 set in routing table 270). In the example, latency service 142 maythen store the resulting latencies of the pings as latencies 160, 162,164, and 166 in latency cache 150.

In an example, routing service 141 and latency service 142 may executeindependently of each other. In an example, if a given IP address (e.g.,IP address 170) is unresponsive to either routing service 141 or latencyservice 142's ping, IP address 170 may be flagged in routing pool 155 asbeing temporarily disabled to avoid waiting repeatedly for attempts toping IP address 170 to time out. In an example, routing service 141flagging IP address 170 as temporarily disabled may result in routingservice 141, routing service 146, latency service 142, and latencyservice 147 skipping IP address 170 for a certain time duration and/or acertain number of pinging cycles. In an example, an IP address (e.g., IPaddress 170) after being unresponsive and/or unavailable for asufficient number of attempts and/or for a sufficient duration, may beremoved from routing pool 155 and placed in a separate inactive list. Inan example the separate inactive list may be checked for reactivatedtarget nodes, for example, on a daily basis. In an example, latencyservice 142 may group latencies 160, 162, 164, and 166 into variousperformance categories. For example, latency 160 may be flagged asunusable due to a response time greater than a maximal threshold value.Similarly, latency 162 may be flagged as high performance, latency 164as medium performance, and latency 166 as low performance due to theirrespective response times. In an example, the performancecharacterization of each IP address (e.g., IP addresses 170, 172, 174,and 176) and latency (e.g., latencies 160, 162, 164, and 166) pairingmay be re-evaluated each time latency service 142 pings a given IPaddress. In an example, features other than latency may be factored intoa decision on prioritization, for example, a number of outstandingrequests sent to a particular IP address, or a request response time ofthe particular IP address. In an example, performance levels may be moreor less granular than the three step grouping of high, medium, and lowperformance in the example above.

FIG. 3 is a flowchart illustrating dynamic advertisement routingaccording to an example of the present disclosure. Although the examplemethod 300 is described with reference to the flowchart illustrated inFIG. 3, it will be appreciated that many other methods of performing theacts associated with the method 300 may be used. For example, the orderof some of the blocks may be changed, certain blocks may be combinedwith other blocks, and some of the blocks described are optional. Themethod 300 may be performed by processing logic that may comprisehardware (circuitry, dedicated logic, etc.), software, or a combinationof both. In an example, the method is performed by a load balancerservice 140 in conjunction with routing service 141 and latency service142.

A plurality of internet protocol addresses is stored in a routing pool,including first, second, and third internet protocol addressesrespectively associated with first, second, and third target nodes of aplurality of target nodes (block 310). For example, discovery service241 may store, in routing pool 155, IP addresses 170, 172, and 174 whichare respectively associated with NICs 250, 252, and 255A. IP addresses170, 172, and 174 may thereby be respectively associated with nodes 210,211, and 212. In an example, discovery service 241 may be configured torepeatedly send requests to a single domain name (e.g., a domain name ofadvertiser 220) and each of nodes 210, 211, and 212 may host a sharedcommon application (e.g., ad services 230, 232, and 235). In a furtherexample, discovery service 241 may later be randomly connected to afourth IP address from sending requests to the domain name of advertiser220, and add IP address 176 associated with NIC 255B to routing pool155. In the example, discovery service 241 may be unable to distinguishthat NIC 255B and IP address 176 belong to a second NIC on node 212rather than another stand alone node. In an example, implementation ofthe routing pool 155 circumvents queries to DNS for requests with actualpayloads by allowing for direct connections to target IP addresses(e.g., IP addresses 170, 172, 174, and 176). In a typical case, a pingwith DNS to a closely situated server may take 15 ms-40 ms, while adirect ping to the IP address of the same server may take 1 ms-10 ms.

Each of the plurality of internet protocol addresses in the routing poolis pinged, including at least the first, second, and third internetprotocol addresses, through each of a first load balancer networkinterface and a second load balancer network interface (block 315). Inan example, routing service 141 may ping IP addresses 170, 172, and 174through both of the virtual network interfaces 187A-B. In the example,routing service 141 may determine that a connection to IP address 170 isfaster through virtual network interface 187A than through virtualnetwork interface 187B. Similarly, a preference may be selected forvirtual network interface 187B to connect to IP address 172, and virtualnetwork interface 187A may be selected to connect to IP address 174.

At least one of a first network route to the first target node, a secondnetwork route to the second target node, and a third network route tothe third target node is updated based on a first plurality of pingresponses (block 320). In an example, routing service 141 may receiveping responses from each of IP addresses 170, 172, and 174 through eachof virtual network interfaces 187A-B. In an example, routing service 141may record the preferred virtual network interface (e.g., 187A or 187B)for connecting to each IP address (e.g., IP addresses 170, 172, and 174)in routing pool 155 to a routing table 270 as a network route (e.g.,network routes 260, 262, and 264). In some examples, routing service 141may also directly update latency cache 150 with ping latencies from thedynamic network route discovery process.

A first communication session is established with the first target nodethrough the first network route, a second communication session with thesecond target node through the second network route, and a thirdcommunication session with the third target node through the thirdnetwork route (block 325). In an example, routing service 141 mayestablish a communication session with each target IP address (e.g., IPaddresses 170, 172, and 174) through each load balancer networkinterface (e.g., virtual network interfaces 187A-B) prior to pinging theIP addresses 170, 172, and 174. In the example, these communicationsessions may be kept open to speed up sending requests through thenetwork routes underlying the communication sessions. In anotherexample, the latency service 142 may establish communication sessionsafter preferred routes have already been selected and stored in routingtable 270. In another example, communication sessions may be establishedwhen the load balancer transmits the first request with an actualpayload to the target IP address. For example, the communication sessionmay be kept open after a response to the request to the target IPaddress is received by the load balancer. In an example, the firstcommunication session is established through network route 260 viavirtual network interface 187A, the second communication session isestablished through network route 262 via virtual network interface187A, and the third communication session is established through networkroute 264 via virtual network interface 187B. In an example, the firstcommunication session is established between a port on VM 116 andanother port on target node 210. In the example, the respective portsmay be associated respectively with an IP address of virtual networkinterface 187A and IP address 170 of NIC 250.

The first, second, and the third internet protocol addresses are pinged(block 330). In an example, the latency service 142 pings each of thetarget IP addresses (e.g., IP addresses 170, 172, and 174) in routingpool 155. In the example, latency service 142 pings the target IPaddresses through a default network route (e.g., network routes 260,262, and 264) associated with the respective target IP address and/ortarget node. In an example, a latency of each target IP address iscomputed based on a ping response from each IP address.

First, second, and third latencies in a latency cache are updated basedon a second plurality of ping responses (block 335). In an example,latency service 142 may record a respective calculated latency (e.g.,latencies 160, 162, and 164) in latency cache 150 for each target IPaddress (e.g., IP addresses 170, 172, and 174) pinged. In an example,latency service 142 may further categorize each target IP address (e.g.,IP addresses 170, 172, and 174) with a performance characteristic basedon a respective latency (e.g., latencies 160, 162, and 164). In anexample, node 210 may be classified as high performance based on latency160, node 211 may be classified as medium performance based on latency162, and node 212 may be classified as low performance based on latency164. In another example, latency service 142's ping to target IP address174 may time out, and target IP address 174 may be classified asnon-operational. In the example, load balancer 140 may not send requestswith actual payload data to target IP addresses classified asnon-operational. In an example, a timeout value that latency service 142waits for a response to a ping may be configurable. In an example, afterdiscovery service 241 discovers IP address 176 associated with NIC 255Bas being an IP address of advertiser 220, routing service 141 may setnetwork route 266 between virtual network interface 187B and NIC 255B asthe default network route for IP address 176. In the example, latencyservice 142 may then ping IP address 176 and record a latency 166associated with IP address 176 in latency cache 150.

A first request directed to the plurality of target nodes is received(block 340). In an example, load balancer 140 may receive a request froma publisher of content (e.g., a news website) for bids for an availablead slot (e.g., a banner ad on the front page). In the example, loadbalancer 140 may be configured to forward the request to advertiser 220to solicit a bid for the ad slot. The first request is determined to besent to the first target node based on the latency cache (block 345). Inan example, latency 164 may have breached a time out threshold therebyremoving IP address 174 and node 212 from contention for receiving therequest. In the example, load balancer 140 may employ any form of randomor pseudo random selection process to decide between forwarding therequest to node 210 vs. node 211. In an example, node 210 is selectedbased on a random distribution. In another example, upon receipt of therequest, the load balancer 140 may assess the request to classify therequest with a priority. For example, the request may include a priorityvalue and/or a timeout value, and the load balancer 140 may assign apriority classification to the request based on the priority valueand/or the timeout value. In an example, a priority value may be basedon an expected response deadline for loading an ad for the ad slot. Apriority value may also be based on historical data relating toeffectiveness of ad placements with a particular publisher (e.g., apublisher whose ad slot generates more click-throughs and/or purchasesmay be in higher demand and therefore receive priority over a lesseffective publisher's ad slot). In an example, a timeout value may becommunicated by a publisher as an effective “last call” for bids, afterwhich bids will be ignored. In another example, a timeout value may becalculated based on historical bid success data for a particularpublisher. In other examples, a publisher may implement dynamicadvertisement routing to enhance the response time of bid requests to adagencies and/or directly to advertisers.

The first request is forwarded to the first target node via the firstnetwork route (block 350). In an example, load balancer 140 may forwardthe first request to node 210 via network route 260. In an example, acommunication session on network route 260 may be established andmaintained in an open state to avoid the first request from having toengage in a handshake process with target node 210. In an example, asecond request classified as high priority, a third request classifiedas medium priority, and a fourth request classified as low priority maysubsequently be received by load balancer 140. In the example, targetnode 210 may be high performance, target node 211 may be mediumperformance and target node 212 may be low performance basedrespectively on latencies 160, 162, and 164. In the example, the secondrequest may be sent to target node 210 via network route 260, the secondrequest to target node 211 via network route 262, and the third requestto target node 212 via network route 264. In an example where latency164 exceeded a latency threshold, the third request may be sent totarget node 211 instead. In such an example, on a later iteration,latency service 142 may again ping IP address 174 associated with node212, and this time, a new latency calculated from the ping response tothe new ping may fall under the latency threshold. The latency servicemay then update latency cache 150 indicating that IP address 174 andtherefore node 212 has been elevated to low performance status. In theexample, another request classified as low priority received by loadbalancer 140 may then be sent to node 212 via network route 264.

FIG. 4 is a flow diagram illustrating target discovery and routeselection in a dynamic advertisement routing system according to anexample of the present disclosure. Although the examples below aredescribed with reference to the flowchart illustrated in FIG. 4, it willbe appreciated that many other methods of performing the acts associatedwith FIG. 4 may be used. For example, the order of some of the blocksmay be changed, certain blocks may be combined with other blocks, andsome of the blocks described are optional. The methods may be performedby processing logic that may comprise hardware (circuitry, dedicatedlogic, etc.), software, or a combination of both. In example system 400,a discovery service 241 and a routing service 141 interface with arouting pool 155 and a routing table 270 to discover target IP addressesand optimize network routes to the discovered target IP addresses.

In an example, routing pool 155 stores a current list of all known IPaddresses of a target ad server farm (e.g., advertiser 220) (block 410).A routing service 141 may ping each IP address in the routing pool 155(e.g., IP addresses 170, 172, 174, and 176) with each load balancernetwork interface in system 400 (e.g., virtual network interfaces187A-B) (block 412). In an example, routing service 141 may determinewhich network interface (e.g., virtual network interfaces 187A or 187B)has the lowest ping response time for each of IP addresses 170, 172,174, and 176 (block 414). In the example, routing service 141 may thensave the route from the fastest network interface (e.g., virtual networkinterfaces 187A or 187B) to each of IP addresses 170, 172, 174, and 176to routing table 270 (block 416). In an example, routing table 270 maybe updated with the network interface (e.g., virtual network interfaces187A or 187B) to use to connect to each of IP addresses 170, 172, 174,and 176 in routing pool 155 (block 418). In some examples, each separateinstance of a load balancer service (e.g., load balancer services 140and 145) may be associated with a separate instance of routing service(e.g., routing services 141 and 146). In other examples, routing service141 and routing service 146 may be components of a singular routingservice that can access each virtual network interface (e.g., virtualnetwork interfaces 187A-D) on each VM (e.g., VMs 116 and 118) in system100. Similarly, routing pool 155 may be shared between load balancerservice instances 140 and 145 and/or stored as separate copies accessedby each load balancer service 140 and 145 separately.

In an example, discovery service 241 accesses a target ad server farm(e.g., advertiser 220), through a DNS address (e.g., a hostname URL)(block 420). In the example, discovery service 241 may perform suchaccess with actual payload data for an ad request, or without payloaddata (e.g., through pinging the hostname URL). In an example, after DNSresolves the hostname URL and allows discovery service 241 to connect tothe target node, discovery service 241 may retrieve the IP address ofthe currently connected target node (block 422). In the example,discovery service 241 may then determine whether the retrieved IPaddress is present in routing pool 155 (block 424). If the IP address isnot present in the routing pool 155, discovery service 241 may add thenew IP address to the routing pool 155 (block 426). In the example, thenew IP address is added to routing pool 155 (block 430). When queried,routing pool 155 then provides an updated list of IP addresses includingthe new IP address (block 432). In an example, discovery service 241 mayupdate routing pool 155 in real time and any additional IP addresses maybe pinged by routing service 141 the next time routing service 141executes. If the IP address is present in the routing pool 155,discovery service 241 may loop back and repeat the access of the targetad server farm (e.g., advertiser 220) through the DNS address (block428). In an example, discovery service 241 may continually execute thediscovery process periodically (block 450). In the example, discoveryservice 241 may be configured to execute more or less frequently basedon a frequency of newly discovered IP addresses. For example, discoveryservice 241 may be configured to execute once a minute, but when no newIP address has been discovered in thirty attempts, discovery service 241may be dialed back to execute once every 5 minutes. In the example, iftwo discoveries are then made within ten attempts, discovery service 241may be reconfigured to execute every five seconds since the twodiscoveries may be indicative of new servers being brought online byadvertiser 220 with a new range of IP addresses.

In an example, routing service 141 may again ping each IP address in therouting pool 155 (e.g., IP addresses 170, 172, 174, and 176) with eachload balancer network interface in system 400 (e.g., virtual networkinterfaces 187A-B) including pinging the new IP address discovered bydiscovery service 241 (block 434). In the example, routing service 141may determine which network interface (e.g., virtual network interfaces187A or 187B) has the lowest ping response time for each of IP addresses170, 172, 174, 176, and the new IP address (block 414). In the example,routing service 141 may then save the route from the fastest networkinterface (e.g., virtual network interfaces 187A or 187B) to each of IPaddresses 170, 172, 174, 176, and the new IP address to routing table270 (block 438). In an example, routing table 270 may be updated withthe network interface (e.g., virtual network interfaces 187A or 187B) touse to connect to each of IP addresses 170, 172, 174, 176, and the newIP address in routing pool 155 (block 440). In an example, routingservice 141 may continually execute to validate the current fastestnetwork route to each target IP address. For example, in a system withten load balancer network interfaces, a routing service wouldcontinually rotate through each load balancer network interface andtarget IP address combination to keep preferred routes up to date in therouting table. In an example, if a target IP address is unresponsivewhen pinged from multiple load balancer network interfaces, a routingservice may skip the remaining load balancer network interfaces for thattarget IP address until a later rotation as the server for the target IPaddress is likely offline.

FIG. 5 is a flow diagram illustrating target prioritization throughlatency detection in a dynamic advertisement routing system according toan example of the present disclosure. Although the examples below aredescribed with reference to the flowchart illustrated in FIG. 5, it willbe appreciated that many other methods of performing the acts associatedwith FIG. 5 may be used. For example, the order of some of the blocksmay be changed, certain blocks may be combined with other blocks, andsome of the blocks described are optional. The methods may be performedby processing logic that may comprise hardware (circuitry, dedicatedlogic, etc.), software, or a combination of both. In example system 500,a routing service 141 and a latency service 142 interface with a routingpool 155 and a latency cache 150 to prioritize target IP addresses forrequests.

In an example, routing pool 155 stores a current list of all known IPaddresses of a target ad server farm (e.g., advertiser 220) (block 510).A latency service 142 may ping each IP address in the routing pool 155(e.g., IP addresses 170, 172, 174, and 176) via a default network routestored in routing table 270 (block 512). In an example, latency service142 may ping the target IP addresses 170, 172, 174, and 176 much morefrequently than routing service 141, since latency service 142 onlypings once per target address per cycle vs. once for each load balancernetwork interface in the case of routing service 141. In an example,latency service 142 determines a latency (e.g., latency 160, 162, 164,and 166) for each IP address in routing pool 155 (e.g., IP addresses170, 172, 174, and 176) (block 514). For example, latency 160 may becalculated based on a ping response time to IP address 170. In anexample, latency service 142 may discard the latency result for thefirst IP address 170 due to the ping to IP address 170 timing out (block516). In an example, discarding a latency result may keep any actual adrequests from being sent to IP address 170 since no entry would be madefor IP address 170 in latency cache 150. In an example, the remaining IPaddresses (e.g., IP addresses 172, 174, and 176) may be sorted intohigh, medium, and low performance bands based on latency cut offs (block518). For example, responses taking over 10 ms may be discarded as timeouts, responses over 7 ms may be classified as low performance,responses over 5 ms may be classified as medium performance, andresponses faster than 5 ms may be classified as high performance. In anexample, IP address 172 may be high performance, IP address 174 may bemedium performance, and IP address 176 may be low performance. In anexample, the sorted IP addresses 172, 174, and 176 may be saved inlatency cache 150 (block 520). Latency cache 150 may then be updatedwith a list of targets for high, medium, and low performance (block522). In an example, IP addresses (e.g., IP addresses 172, 174, and 176)may be stored in entries in latency cache 150 along with numericallatency values. In another example, latency cache 150 may store IPaddresses (e.g., IP addresses 172, 174, and 176) in performance bandswithout numerical latency values.

In an example, routing service 141 again pings each IP addresses (e.g.,IP addresses 170, 172, 174, and 176) in routing pool 155 with each loadbalancer network interface (e.g., virtual network interfaces 187A-D)(block 530). In the example, routing service 141 may determine thatvirtual network interface 187B now has lower latency to IP address 170than virtual network interface 187A (block 532). Routing service 141 maythen update routing table 270 to send messages to IP address 170 throughvirtual network interface 187B instead of virtual network interface 187A(block 534). In an example, latency service 142 may again retrieve acurrent list of IP addresses (e.g., IP addresses 170, 172, 174, and 176)from routing pool 155 (block 540). In the example, routing pool 155 maysend the current list of IP addresses (e.g., IP addresses 172, 174, and176) (block 542). In an example, IP address 170 is included in the listfrom routing pool 155 even though latency service 142's previous ping toIP address 170 timed out. In an example, latency service 142 pings eachIP addresses (e.g., IP addresses 172, 174, and 176) in routing pool 155,including pinging IP address 170 through virtual network interface 187Binstead of virtual network interface 187A (block 544). For example,routing service 141 may have updated the network route in routing table270 for IP address 170 prior to latency service 142 pinging IP address170 again. In an example, latency service 142 may determine that IPaddress 170 now sorts into the medium performance band (block 546). Inan example, latency service 142 saves IP address 170 to latency cache150 (block 142). In the example, IP address 170 is added to the list ofmedium performance targets in latency cache 150 (block 550). In someexamples, no other changes may have occurred for the performance bandingof IP addresses 172, 174, and 176. In other examples, the performancebanding of IP addresses 172, 174, and 176 may also be readjusted basedon the latest pinging by latency service 142, and may be updated inlatency cache 150. In an example, blocks 512-522 may be performedindependently of blocks 530-540, with the latency service 142 executingmultiple times to test the current performance of the IP addresses 170,172, 174, and 176 for each time the routing service 141 tests forpreferable network routes.

In an example, a system hosting a load balancer service along with arouting service and a latency service may have eight, sixteen, or evenone hundred or more network interfaces whether physical or virtualized.In the example, the routing service may require significantly longer toping each IP address in a routing pool than the latency service, becauseof the multiplicative effect on the number of pings that are required towork through the list of IP addresses caused by the addition of morenetwork interfaces. In addition, the latency service may be configuredwith a more aggressive time out than the routing service where therouting service may be confirming whether a target node is active, whilethe latency service is prioritizing whether the given target node isperforming well enough to be used for a request with an active payload.Similarly, the routing service may trigger significantly more timeouts(e.g., where multiple routes to the same struggling or inoperativetarget node are tested). For example, in a system with ten networkinterfaces, the latency service may be configured to time out after 20ms, while the routing service may be configured to time out after 200ms. In the example, if the ten network interfaces are used to access onehundred target IP addresses, the latency service would take, as a roughupper bound, at most 2,000 ms to execute, (e.g., 20 ms to time out andone hundred target IP addresses to try). In the example, 20 ms may beconfigured as a lower bound for “low performance” connections. In thesame example, the routing service may take up to 200,000 ms to executeif every possible combination timed out. In a typical system with tennetwork interfaces, the routing service may typically take fifteen totwenty times as long to execute as the latency service. Therefore, theseparation of the polling of the latency service and the routing serviceallows prioritization and performance data in the latency cache to besignificantly more up to date. In an example, the latency service mayalso consider a wider range of data than the latest ping result indetermining a performance band for a given target node. For example, arolling and/or weighted average ping response time over a given timeperiod (e.g., five minutes) may be used. In an example, ping responsetime may be combined with other factors, such as a quantity ofoutstanding requests, to determine the performance band for a giventarget node. For example, a target node that has not responded yet totwo or more previous requests may be dropped by a performance band(e.g., high to medium or medium to low).

FIG. 6 is a flow diagram illustrating dynamic request handling in adynamic advertisement routing system according to an example of thepresent disclosure. Although the examples below are described withreference to the flowchart illustrated in FIG. 6, it will be appreciatedthat many other methods of performing the acts associated with FIG. 6may be used. For example, the order of some of the blocks may bechanged, certain blocks may be combined with other blocks, and some ofthe blocks described are optional. The methods may be performed byprocessing logic that may comprise hardware (circuitry, dedicated logic,etc.), software, or a combination of both. In example system 600, a loadbalancer service 140 and a latency service 142 interface with a latencycache 150 to send requests to selected target IP addresses.

In an example, load balancer service 140 receives a first requestdirected at a target ad server farm (e.g., advertiser 220) (block 610).In the example, load balancer service 140 determines that the request isa high priority request (block 612). For example, the request may beflagged with a time stamp indicating a short window for responding withan ad bid for an ad slot. Alternatively, the source of the request(e.g., a publisher) may be flagged in load balancer service 140 asparticularly effective and therefore responding with a bid on time isparticularly important. In an example, load balancer service 140requests a high performance target from latency cache 150 (block 614).In the example, latency cache 150 may respond by sending load balancerservice 140 the current list of high performance IP addresses (block616). In an example, load balancer service 140 forwards the firstrequest to target node 210 included in the list of high performance IPaddresses (e.g., IP address 170) (block 618). In an example, IP address170 may be selected from the list of high performance IP addressesrandomly by load balancer service 140. In another example, latency cache150 may send only one random IP address that is flagged as highperformance rather than the whole list of high performance IP addresses.In an example, load balancer service 140 tracks which target IPaddresses have recently received requests. For example, load balancerservice 140 may ensure that no single target IP address is flooded withrequests. In the example, if every load balancer service (e.g., 140 and145) sent each request to the target IP address in latency cache 150with the current fastest response time, the target node associated withthe target IP address may be unable to respond to the requests quicklyenough to respond in real-time, resulting in the queueing of requestsand sub-optimal response times. In an example, rather than sortingtarget IP addresses into performance bands, an alternative sortingmethod may be used (e.g., sorting by ping response times directly). Insuch an example, a request may be sent to any target IP address whosecalculated response time may meet a critical timeout value forresponding to the request.

Latency service 142 may execute concurrently with the processing of thefirst request by load balancer service 140. In an example, latencyservice 142 may ping each IP address (e.g., IP addresses 170, 172, 174,and 176) in routing pool 155 via a network route (e.g., network routes260, 262, 264, and 266) stored in routing table 270 (block 620). In anexample, latency service 142 may determine a latency (e.g., latencies160, 162, 164, and 166) for each IP address 170, 172, 174, and 176 inrouting pool 155 (block 622). In the example, the latency result 160 ofIP address 170 may be downgraded to low performance due to the responsetime of the latest ping from latency service 142 (block 624). In anexample, traffic to IP address 170 may have become congested due to itsprevious low latency and high performance. In another example, a switchin the route to IP address 170 may be restarting for maintenance. In anexample, latency service 142 updates latency cache 150 indicating thatIP address 170 is now low performance (block 626). Latency cache 150 maysave the updated performance bands for the various IP addresses 170,172, 174 and 176, including saving IP address 170 as low performance(block 628).

In an example, load balancer service 140 may receive a second requestdirected at the target ad server farm (e.g., advertiser 220) (block630). In the example, load balancer service 140 determines that thesecond request is low priority (block 632). For example, the secondrequest may have a response time deadline that should be met even by alow performance target node (e.g., the updated node 210). Alternatively,historical data may show that bids to the publisher for the secondrequest rarely win an ad slot and/or generate low returns even when bidsare won. In an example, load balancer service 140 requests a lowperformance target from latency cache 150 (block 634). In the example,latency cache 150 responds by sending a current list of low performanceIP addresses, including IP address 170 (block 636). Load balancerservice 140 then forwards the second request to node 210 (e.g., IPaddress 170) selected at random from the list of low performance IPaddresses (block 638). In an example, load balancer service 140 keepstrack of where requests have been sent. In an example, load balancerservice 140 receives a third request directed at the target ad serverfarm (e.g., advertiser 220) (block 640). In an example, load balancerservice 140 may receive the third request prior to receiving responsesto the first two requests from IP address 170. In the example, the thirdrequest may be determined to be low priority (block 642). In an example,load balancer service 140 may again request an updated list of lowperformance IP addresses from latency cache 150, and may receive anupdated list of low performance IP addresses. In another example, loadbalancer service 140 may re-use the previous list of low performance IPaddresses due to the temporal proximity between receiving the second andthird requests. In an example, load balancer service 140 sends the thirdrequest to target node 211 to avoid flooding target node 210 withrequests (block 644). In the example, both IP address 170 and IP address172 may be on the list of low performance IP addresses, but IP address170 may be removed from contention for receiving the third request dueto the first two outstanding requests being processed by target node210.

In an example, a connection is constantly maintained between a networkinterface (e.g., virtual network interfaces 187A-D) of system 100, andeach target IP address (e.g., IP addresses 170, 172, 174, and 176) ofadvertiser 220 to allow a request to be sent to a selected IP address(e.g., IP addresses 170, 172, 174, or 176) without requiring a newhandshake to establish a connection. In an example, connecting directlyto a target IP address bypassing DNS may decrease latency by up to 20ms. In an example, by eliminating sending requests to target nodestemporarily experiencing networking or other difficulties, failures andother outliers may be greatly reduced. In various embodiments, employingdynamic advertisement routing may reduce average response times for adbid requests from 500 ms-1,000 ms down to 200 ms or less whileeliminating the majority of bids lost to timeout. In an example, thelarger the system grows (e.g., with more network interfaces and moreconnections) the better the performance of the selected top performingnetwork route may be. For example, if one hundred network interfaces aretested for connecting to a target IP address, the top performer of theone hundred connections would be likely be at least in the top tenpercent of possible routing performances. The more target nodes areavailable, the more high performing load balancer network interface andtarget node combinations may be found. As such, the larger the system,the stronger the performance of a system executing dynamic advertisementrouting. For example, in a system with one hundred target IP addresseswith only one load balancer network interface and therefore selecting amedian performing network route for each target IP address, potentiallyonly five of the target IP addresses may qualify as high performancetargets. However, by increasing to ten load balancer network interfaceswith dynamic advertisement routing to select for the top performingroute of the ten possible routes for each target IP address, thirty ofthe target IP addresses may then qualify as high performance targets.With one hundred network interfaces, potentially seventy of the targetIP addresses may qualify as high performance due to being able to selectfor extremely high performing network routes to each target IP address.

It will be appreciated that all of the disclosed methods and proceduresdescribed herein can be implemented using one or more computer programsor components. These components may be provided as a series of computerinstructions on any conventional computer readable medium or machinereadable medium, including volatile or non-volatile memory, such as RAM,ROM, flash memory, magnetic or optical disks, optical memory, or otherstorage media. The instructions may be provided as software or firmware,and/or may be implemented in whole or in part in hardware componentssuch as ASICs, FPGAs, DSPs or any other similar devices. Theinstructions may be executed by one or more processors, which whenexecuting the series of computer instructions, performs or facilitatesthe performance of all or part of the disclosed methods and procedures.

It should be understood that various changes and modifications to theexample embodiments described herein will be apparent to those skilledin the art. Such changes and modifications can be made without departingfrom the spirit and scope of the present subject matter and withoutdiminishing its intended advantages. It is therefore intended that suchchanges and modifications be covered by the appended claims.

The invention is claimed as follows:
 1. A system of network latencyoptimization for an online advertisement auction system, the systemcomprising: a memory storing a latency cache and a routing pool, whereinthe routing pool stores a plurality of target addresses for anadvertiser including a first target address and a second target address;a plurality of network interfaces including a first network interfaceand a second network interface; and a load balancer executing on one ormore processors to: determine a first plurality of latencies to each ofthe plurality of target addresses stored in the routing pool, includinga first latency of a first network route from the first networkinterface to the first target address, a second latency of a secondnetwork route from the second network interface to the first targetaddress, a third latency of a third network route from the first networkinterface to the second target address, and a fourth latency of a fourthnetwork route from the second network interface to the second targetaddress; establish a first session through the first network route and asecond session through the third network route, wherein a plurality ofcurrent latencies are stored in the latency cache including a currentfirst latency of the first network route and a current third latency ofthe third network route; responsive to receiving a first request from apublisher for a bid for an advertisement slot and based on the latencycache, select the first target address via the first network route forsending the first request to the advertiser; and determine a fifthlatency of a fifth network route from the second network interface tothe first target address and a sixth latency of a sixth network routefrom the second network interface to the second target address, whereinthe first session through the first network route and the second sessionthrough the third network route are kept alive while the fifth latencyand the sixth latency are determined.
 2. The system of claim 1, whereinthe first network route and the third network route are stored in arouting table respectively as a first selected route to the first targetaddress and a second selected route to the second target address.
 3. Thesystem of claim 2, wherein the latency cache stores current latencies ofthe first network route and the third network route based on the firstnetwork route and the third network route being included in the routingtable.
 4. The system of claim 3, wherein a latency service periodicallypings each target address of the plurality of target addresses through arespective selected route to each respective target address.
 5. Thesystem of claim 2, wherein the load balancer further executes to replacethe first network route with the fifth network route as the firstselected route to the first target address.
 6. The system of claim 5,wherein a current fifth latency of the fifth network route is stored inthe latency cache after the fifth network route becomes the firstselected route.
 7. The system of claim 5, wherein the load balancerfurther executes to responsive to receiving a second request from asecond publisher for a bid for an advertisement slot and based on thelatency cache, select a third session through the fifth network routefor sending the second request to the first target address.
 8. Thesystem of claim 1, wherein a routing service periodically pings each ofthe plurality of target addresses in the routing pool from each of theplurality of network interfaces.
 9. The system of claim 1, wherein thefirst request is high priority and a second request is low priority. 10.The system of claim 9, wherein the second request is forwarded to thesecond target address based on the current third latency being higherthan the current first latency.
 11. The system of claim 1, wherein athird target address of the plurality of target addresses is discoveredbased on a request sent to a domain name associated with the firsttarget address, and a routing service pings the third target addressfrom each of the first network interface and the second networkinterface.
 12. The system of claim 11, wherein a third session isestablished through a seventh network route from the first networkinterface to the third target address, and the third session is keptalive while the routing service pings the third target address throughan eighth network route from the second network interface to the thirdtarget address, and then pings the third target address again through adifferent ninth network route from the second network interface to thethird target address.
 13. The system of claim 1, wherein the loadbalancer executes instructions to select the first network route basedat least in part on a response deadline for loading an advertisement forthe advertisement slot.
 14. The method of claim 1, wherein selecting thefirst network route is also based at least in part on a responsedeadline for loading an advertisement for the advertisement slot.
 15. Amethod of network latency optimization for an online advertising auctionsystem, the method comprising: determining a first plurality oflatencies to each of a plurality of target addresses for an advertiserstored in a routing pool, including a first latency of a first networkroute from a first network interface of a plurality of networkinterfaces to a first target address of the plurality of targetaddresses, a second latency of a second network route from a secondnetwork interface of the plurality of network interfaces to the firsttarget address, a third latency of a third network route from the firstnetwork interface to a second target address of the plurality of targetaddresses, and a fourth latency of a fourth network route from thesecond network interface to the second target address; establishing afirst session through the first network route and a second sessionthrough the third network route, wherein a plurality of currentlatencies are stored in a latency cache including a current firstlatency of the first network route and a current third latency of thethird network route; responsive to receiving a first request for bids onan online advertising slot from a publisher and based on the latencycache, sending the first request to the advertiser via the first networkroute; and determining a fifth latency of a fifth network route from thesecond network interface to the first target address and a sixth latencyof a sixth network route from the second network interface to the secondtarget address, wherein the first session through the first networkroute and the second session through the third network route are keptalive while the fifth latency and the sixth latency are determined. 16.The method of claim 15, further comprising storing the first networkroute and the third network route in a routing table as a first selectedroute to the first target address and a second selected route to thesecond target address.
 17. The method of claim 16, further comprising:periodically pinging each target address of the plurality of targetaddresses through a respective selected route to each respective targetaddress.
 18. The method of claim 16 further comprising, replacing thefirst network route with the fifth network route as the first selectedroute to the first target address; storing a current fifth latency ofthe fifth network route in the latency cache; and selecting a thirdsession through the fifth network route for a second request to thefirst target address.
 19. The method of claim 15, further comprisingperiodically pinging each of the plurality of target addresses in therouting pool from each of the plurality of network interfaces.
 20. Themethod of claim 15, further comprising discovering a third targetaddress of the plurality of target addresses based on a request sent toa domain name associated with the first target address; and pinging thethird target address from each of the first network interface and thesecond network interface.
 21. The method of claim 20, further comprisingestablishing a third session through a seventh network route from thefirst network interface to the third target address; and keeping thethird session alive while the routing service pings the third targetaddress through an eighth network route from the second networkinterface to the third target address, and then pings the third targetaddress again through a different ninth network route from the secondnetwork interface to the third target address.
 22. A computer-readablenon-transitory storage medium storing executable instructions of networklatency optimization for an online advertising auction system, whichwhen executed by a computer system, cause the computer system to:determine a first plurality of latencies to each of a plurality oftarget addresses for an advertiser stored in a routing pool, including afirst latency of a first network route from a first network interface ofa plurality of network interfaces to a first target address of theplurality of target addresses, a second latency of a second networkroute from a second network interface of the plurality of networkinterfaces to the first target address, a third latency of a thirdnetwork route from the first network interface to a second targetaddress of the plurality of target addresses, and a fourth latency of afourth network route from the second network interface to the secondtarget address; establish a first session through the first networkroute and a second session through the third network route, wherein aplurality of current latencies are stored in a latency cache including acurrent first latency of the first network route and a current thirdlatency of the third network route; responsive to receiving a firstrequest for bids for on an online advertising slot from a publisher andbased on the latency cache, send the first request to the advertiser tothe first target address via the first network route; and determine afifth latency of a fifth network route from the second network interfaceto the first target address and a sixth latency of a sixth network routefrom the second network interface to the second target address, whereinthe first session through the first network route and the second sessionthrough the third network route are kept alive while the fifth latencyand the sixth latency are determined.
 23. The medium of claim 22,wherein the executable instructions further cause the computer system toselect the first network route based at least in part on a responsedeadline for loading an advertisement for the advertisement slot.